A few years ago, this song came out of nowhere, "Pumped Up Kicks" from Foster The People, an unsigned band from LA. It became one of 2011's biggest hits.

(SOUNDBITE OF SONG, "PUMPED UP SUP KICK")

GREENE: Song, as you can hear, has a summer party sound. The lyrics, though, tell a much darker story.

MARK FOSTER: The fact that song culturally caught on really surprised me.

GREENE: Mark Foster leads the band.

FOSTER: It was about isolation and teenage culture, you know, and kind of the trends in youth violence.

GREENE: And isolation is a theme that kept coming up when Foster sat down to chat with us recently. He and his band are out tomorrow with their second album. It's called "Supermodel."

Mark Foster grew up in Cleveland, Ohio. When he was 18, he moved with a friend to Los Angeles with big plans for a music career. It was culture shock.

FOSTER: LA is a big city, you know. And LA is a weird city. And...

GREENE: What do you mean?

FOSTER: Well, it's just - it's, you really got to have a strong sixth sense to be able to kind of navigate the waters because the weird thing about LA is just - especially in Hollywood - is just like, the entertainment industry is kind of bizarre. It was the first time that I realized that people that were mentally ill also happened to be in like, powerful positions.

(LAUGHTER)

FOSTER: It was like wow, this is really weird. Like, that guy is like, really eccentric. How does he survive and ...

GREENE: And thrive, to be an executive

FOSTER: Yeah, but he thrives- you know, is an executive or whatever it is. It's just like wow, that's really interesting. So I think that part of the big adjustment was kind of like, learning socially the differences of living in Los Angeles compared to Cleveland.

GREENE: You've talked about - that you struggled with drug use for a time. And your friends were very worried. I mean, how bad did it get?

FOSTER: Well, I mean, it got pretty bad. You know, I was young enough to where I still felt pretty invincible. And so it really took like, my friend - who I moved out to LA with, actually - was kind of the one that opened up my eyes, 'cause I hadn't seen him in a few months. I had kind of gone off the deep end. I don't know, I call those my Gonzo years - you know, my Hunter S. Thompson years. That's kind of what it felt like.

Just being - I felt like the young kid in the room with just big eyes, and I was just kind of watching everything happen around me. And so, I mean, it was pretty grim. You know, my parents cut me off and I was just like, you know, I was scrounging change for food. And my friend ran into me and he just - he started crying. And that kind of - that was the first thing that shook me up 'cause this was like a kid that partied with me for a lot of it, you know. And I was like, wow, it must be serious if he's worried - just 'cause I was so skinny.

GREENE: You have a song on the new album called "Fire Escape," that is about Los Angeles. And it strikes me as really introspective.

(SOUNDBITE OF SONG, "FIRE ESCAPE")

GREENE: What's this about?

FOSTER: I mean, it's about LA. It's about the city and kind of - I guess to me, "Fire Escape" feels kind of just like the old man on the hill that really doesn't say much but has been kind of just watching his whole life; watching patterns and people and, you know, friends come and go . And he's just kind of reflecting on the place that he grew up in and the life he lived.

(SOUNDBITE OF SONG, "FIRE ESCAPE")

GREENE: The tough times you've had in that city kind of on your mind as you sing this song?

FOSTER: Yeah. Yeah. LA - you know, Los Angeles, I guess, has been my muse for a long time. And I love LA, creatively. LA gives me a lot. LA is a city of extremes. People come here from all over the world that have these like, giant ideas, and they put everything into it. And some people just fall flat on their face, and some people, you know, shoot like a rocket.

GREENE: And Foster knows something about soaring. After his struggles with drugs, he formed his band, and their early hit was "Pumped Up Kicks." There were a tour dates. Columbia Records signed the band on. In a sense, it was everything Mark Foster had worked for. But then he experienced a different kind of isolation. He says he got so caught up in the attention and the desire to ride that wave perfectly, he forgot about some of the key relationships in his life. In between albums, Mark Foster spent a lot of time grappling with the instant success.

FOSTER: After making that first record and doing it, I was like OK, well, what next? I'm like, wait; now I have to make another record?

(LAUGHTER)

FOSTER: Shouldn't I be like, trying to learn some other art form now that - like, some big, impossible puzzle that I can like, spend the rest of my life trying to figure out? And so, I think, you know, I had to step back and kind of re-evaluate my life and, I think, raise the ceiling in the sky of possibility and make the vision bigger, so I can keep running at the pace that I was running at before.

GREENE: You're 30 years old. You've got this new album, and one of the songs is "Coming of Age."

(SOUNDBITE OF SONG, "COMING OF AGE")

GREENE: After everything you've been through - the downs, the ups in LA and kind of this big hit and now, kind of moving on from there - I mean, what does "Coming of Age" mean to you?

FOSTER: "Coming of Age" is like - kind of like a confession. It's kind of like that moment of clarity after getting off of tour, and looking around for the first time peripherally, and seeing - I guess just kind of seeing the people that were close to me in my life that I had hurt along the way, in my hyper focus of trying to survive the tidal wave that came at me and my band.

GREENE: And what did the people you hurt along the way feel like now? I mean, are you kind of getting closer to them again?

FOSTER: (Laughter) Yeah. I mean, I think that that there is like, a good amount of grace given to me by family and friends, based on the circumstances, you know. But going into this next record and this next touring cycle, I've been trying to figure out how to achieve balance. I'm a really extreme person, and balance is probably the hardest thing for me to maintain. So I think that's kind of the key to the success - and not repeating the same mistakes.

GREENE: Mark Foster, it's been a real pleasure talking to you. Thanks so much, and best of luck with the album.